Dead front safety switch



June 12, 1934. 1,962,867

F. S. GREEN DEAD FRONT SAFETY SWITCH 5 Sheets-Sheet 1 Filed Aug. 18,1930 VENTOR Y0 5. GREEN BY M ATTORNEY 5 June 12, 1934.. F. s. GREEN1,962,867

DEAD FRONT SAFETY SWITCH Filed Aug. 18, 1950 s Sheets-Sheet 2 June 12,1934. F. s. GREEN DEAD FRONT SAFETY SWITCH Filed Aug. 18, 1950 3Sheets-Sheet 3 INVENTOR F10 m S- GREEN LZuL/I/ r J ATTORNEYS Iture.

Patented June 1 2, 1934 PATEN OFFICE 1,982,887 I nun nosrr sm'rr swrrcnFloyd 8. Green, St. Louis, Mo., slim to Frank Adam Electric Ca, St.Louis, 110., a corporation of Missouri Application August is, 1m, SerialNo. 475,945 8 Claims. (oi. 200-114) This invention relates to dead frontsafety switches and more particularly to improvements in enclosedswitches wherein the operation of the switch is effected by manipulationof the switch 6 door or cover for the switch enclosure.

, An object of my invention lies in the provision of improved switchoperating means.

A furtherobject of this invention is to provide a fuse switch andenclosure therefor, in which 10 the fuses are mounted on the door of theenclosure and both ends thereof entirely disconnected, by a singlemovement, from live elements of the device when the door is in openposition. In accomplishing this object, as stated above, the fuses 16are disposed. on the inner surface of the door, which, when opened,moves the fuses out of the enclosure and into a position where they maybe readily handled without danger of contact with any of the liveportions of the switch struc- Another object of my invention is toprovide an enclosed, externally operated fuse and switch assembly, whichby reason of' the relative disposition of switch and fuse parts,requires less space than the ordinary switches of similar type andcapacity.

Yet another object of my invention is toprovide improved means, in aswitch of the type demribed, for locking the switch in either on or 80 oposition, the means being operative to prevent actuation of the switchwhen the switch cover is closed.

A further object of my invention is to provide means, in connection witha switch of the class 86 named, which prevents the door being closed atsuch times-when the switch blades are disposed intermediate their on andofl" positions. Thus, in order to close the door, it is necessary thatthe switch blades be either positioned so that,

so upon closure of the door, they will make a positive contact with theswitch terminals, or, in the "ot[ condition of the switch, positioned ata suitable, safe distance from the switch terminals.

Still another object is to provide, in combination with switch or fuseelements carried, as'by a door of an enclosure therefor, means enablingsuch elements to be moved between predetermined positions on such door,and yet which positively serted or removed without disturbing theremainder of the installation, the units being so constructed as to beof almost universal application in switchboard or panelboardconstruction. For

example, one of such units may be used as a main disconnect, and othersthereof disposed in rows or tiers and compactly arranged to-utilize tobest advantage a limited available space.

An additional object is the provision, in a device of the type abovereferred to, of means whereby all of the fuse connections are certain tobe made or broken together, and with which there is no possibility thatsome of the poles of the switch and fuse assembly may remain connectedwhile others are disconnected.

These and other objects and advantages will appear as the descriptionproceeds and from the accompanying; drawings which illustrate apreferred embodiment of my invention.

Fig. 1 of the drawings is a front elevation of my switch with the doorin open position, showing a plan view of theunder side of the door andparts carried thereby, a portion being broken away to show certain partsemployed for actuating the fuse block; Fig. 2 is a sectional side viewwith the switch in closed position; Fig. 3 is a plan view, the trim anddoor having been removed to more clearly show certain structuralfeatures of the enclosure; Fig. 4 is a plan view, showing the switchactuating member and indicating means therefor; Fig. 5 is a plan view ofa doublethrow switch embodying features of my invention; Fig. 61s a sideelevation of the switch shown in Fig. 5, and Fig. 7 is a perspectiveview of a switch clip in connection with a device known in the art asan. arc snufl-ou In the present embodiment of my invention,

I provide a switch enclosure or housing, whereby my device is readilyadaptable for assembly in a panelboard or switchboard. It will beunderstood, however, that the application of my switch is in no waylimited, and may be employed whereever an ordinary knife, or safety-typeswitch is adaptable. Thus. in the present embodiment, I

provide a frame member which supports the'door and trim, and enclosesthe switch on three sides.

Side walls 5 extending from'a back 6, are provided at each outer marginwith inturned flanges 'l which are tied together at the rear or hingedserves as a rabbet for the free end of the door. In the particularconstruction'shown, the ends of the switch enclosure are left open, sothat when disposed in rows or tiers, a free circulation of air ispermitted through the assembly, for cooling purposes. Obviously, ifdesired, the switch may be fully enclosed. The door 10 formed of sheetmaterial of a suitable thickness to insure rigidity, is preferablyconnected by hinges 11 to the angulate tie strip 8, the strip beingrecessed to permit the hinges to be mounted flush with its uppersurface. To give a finished appearance to the structure, I provide aframing-plate, or trim 12, secured to the switch frame at the flange 7,by means of the screws 13. It will be noted that the door is not hinged,or otherwise operatively connected to the trim, a construction commonlyemployed in the manufacture of panelboards and switch enclosures, hencethe trim may be removed without disturbing the door or affecting, in anyway, the operation of the switch.

Secured to the back 6, by screws or other suitable means, (not shown) isa switch base 14, preferably of molded insulating material. On the base14 are mounted switch terminals or clips 15, which are arranged inpairs, as best appears in Fig. 3, and adapted to be engaged by blademembers 16, carried by the door, as will hereinafter be described. Pins17, disposed through jaw portions 18 of the switch terminals, serve tomaintain the Jaw portions in parallel alignment for full surfaceengagement with their coacting blade member. The switch terminals areseated on, and directly connected to conducting straps 19; screws 20,inserted, by preference, from the under side of the base block. servingto secure the straps and terminals together, and to the base block. Aswill appear from Fig. 1, one end of each strapis bent upwardly to engagea side of the terminal mounted thereon, thereby preventing said terminalfrom turning, and becoming misaligned with respect to its associatedknife blade. The opposite end of the strap 19 is provided with aconnector or lug 21.

The blade members 16, hereinbefore mentioned, are arranged in pairs onan insulating base 22,

i and each, by preference, is of angulate construction, having a portion23 which extends away from the base for engagement by a terminal member.The pairs of blade members are adapted to be connected by fuses 24, thefuses being disposed in suitable fuse clips 25, which are directLvsecured to the blade members. Although I have described the insulatingbases such as 14 and 22, as each formed of a separate single piece ofmaterial, it is sometimes desirable in installations of the largercapacities to provide a separate insulating base for each of theterminals and fuse clips.

The base 22 is mounted on a slidable plate 26, adapted for movement, inthe present example, parallel to the plane of the door, and transverselyto the paired terminal members 15. Thus, the plate is provided withextended apertures or slots 27; and pins 28, disposed through the slotsand secured to the door are provided with enlarged head portions servingto maintain the plate against the door, and in movable relation thereto.

By preference, the relative disposition of the parts already describedis such that the blade members 16 are in' engaging alignment with theterminal members 15, when the plate 26 is in one of its extremepositions with reference to the door. This condition is illustrated inFig. 1 of the drawings. The plate and parts carried thereby, may bemoved (by means to be hereinafter described) to their other extremeposition relative to the door, as limited by the extent of the slots, inwhich position the blade members are moved out of the planes of theterminals,

and positioned to clear the terminals by a substantial margin when theswitch door is closed.

To prevent the door from being closed when the switch parts are disposedin any other than the two definite positions described above, I provide,on the plate 26, flanges 29, the .end portions 30 of which tend to abutthe angulate tie strip 8. The tie strip 8 is provided with slottedapertures 31, disposed in pairs, each slot being suitable to accommodateone of the end portions 30 of the flanges 29. The slots comprising eachpair are relatively spaced at a distance equal to the length of travelof the plate, hence when thswlate is positioned at either of its limitsof travel, each flange is in register with one of the sip and the doormay be closed. In closed pos ion of the door, the flanges extend throughthe slots as shown in Fig.2.

For actuating and controlling the movement of the plate 26 relative tothe door, I provide a circular disc 32, disposed in an extended aperture33 in the plate. The disc 32 is secured in eccentric relation to a disc34, and to an actuator 35 disposed on the outer surface of the door. Theassembly of actuating members, comprising the disc or eccentric 32, thedisc 34 which forms a bearing for the assembly and the actuator 35, isadapted for rotation within the limits of an angle of 180 degrees. Suchrotation causes the plate and parts carried thereby to be moved from theswitch on position to the switch "of!" position or vice versa.Obviously, substantial or operating movement of the above mentionedparts can be accomplished only when the door is opened sufiiciently towithdraw the flange portions 30, from the slots 31. It will appear thatthe rela- 'tion of the plate 26 and disc 32 is such that the disc andassociated parts will tend to prevent any casual or unintended movementof the plate, the disc or cam 32 serving to position the plate on thedoor, except as the plate may be shifted by movement of the actuator 35.

The actuating member 35, in the present example being of disc form, isadapted for manipulation by a pair of projecting ear portions 36. Also,as means for indicating the switching position of the blade members, Iprovide a notch 37 in theactuator 35, which renders one or the other ofthe words "oi!" or on" visible, depending upon the relative position ofthe switch parts. These words, or other suitable indicia of switchingconditions, are registered, one diametrically opposite the other, on theupper surface of a name plate 38, the words being disposed within thearea covered by the actuating member 35. Also the indicla are arrangedrelative to the limit positions of the notch 37, so that one or theother legend will necessarily be uncovered when the door is closed. Inaddition to the indicia showing the position of the switch blades, asuitable card holder or the like 39, may be employed to designate theparticular circuit to which the unit is applied.

A handle 40, or other suitable door manipulating device is arranged atthe outer or free end of the door, and in the present embodiment of myinvention, I provide a non-locking, staying device 41 which coacts withthe tie strip 9 for maintaining the door in closed position. I may,however, provide any other suitable means for keeping the door closed,such as a key actuated lock, (not shown), mounted in addition to thestaying device 41, or a pair of eye members, for receiving a padlock orthe like. Such a provision, in connection with the switch construchereinwhen particularly advant'h, means gcous, since, by locking the door inclosed position,

upon closing the dean-cannot the doorisagainunlockedand-opened,

The features of my invention-may beembothed in asingle frame, a twopole, double-throw switch comprising a pair of single throw switches.such as are shown in the figures heretofore In this device, means areprovided which prevent individual switching units from being in the.on'?

position-simultaneously. Further means, pref-" erably of the naturedescribed in connection with the single pole switch, are provided, whichpermit of the door being closed only when both units are in off"position, or when one is in -off".

and the other in on""position. This-"provision may correspond to thearrangement of slots 31 and strip portions 30, discussed above andappearing in Fig. 1. Both sets of contacts are pre,-.

vented from concurrent engagement, in the construction of Fig. 6, by thefact that the setting of the blocks 22 on the door, is such thatwheneither is in the on position, it acts as a stop, to prevent theother from being brought into the 011" position. This arrangement willclearly appear from Fig. 6, showing the switch to the right of thefigure in "o position and that on the left, in the on position.' .Itisclear that the spacing between blocks 22 being less than that betweenthe companion blade 23 and clip 15, the open switch cannot, in thissituation,-

be closed.

While the arrangement of double sets of blocks and contacts is preferredsolely. for manufac-v turing reasons, it will appear obvious that thestructure of Figs. 1 et seq., may be utilized as a.

the thickness of a switch blade 23. In operation,

when the switch blade iswithdrawn from the clip, the portions 44 underthe action of the garter spring are moved into the path of the blade andthe are drawn between the blade and clip is quickly extinguished. Fromthe foregoing description it may be seen that I provide a fuse switch ofsimple construction which, by reason of the relative disposition offuses and switch blades, requires less space than ordinary switches 1'its type, and which allows a re-fusing oper ion to be accomplishedwithout danger to an operator; 7

While I have shown and described a'sing'le particular embodiment of myinvention, I realize that many-changes may be made, that certain partsmay be added, dispensed with or interchanged without departing from thespirit and full intended scope of the invention. I I claim: g 1. In aswitch assembly, a switch frame having an insulating base, with switchterminals mounted thereon, a hinged cover, bladecarrying} relative tosaid ma s ca i i 1 m an .a man the - switch-actuatingmovement in a planetransverse to theclosure, and camminfg means carried by the closure andhaving an operating portion extendingthrough said closure, said meansbeing operable only when the closure is in open position, forpositioningthe contacts, selectively, with respect to said plane, and maintainingthe position of said movable contacts, relative to the closure.

3.Inaswitch assemblvincludingahousing and stationary contacts within thehousing, a door for the housing, complementarycontacts carried by. thedoor, means for moving said last namedcontacts relative to the door,said means being operable to move said door contacts only when the dooris in open position, means preventing closure of the door, except inpredeter mined positions of the contacts on the door, and indicia ofswitching condition on said door for indicating the switching relationbetween said door-carried contacts and said stationarycontacts, thevisibility ofsaid indicia being determinedby the position of saidcontact moving means. F

4. In a dead-front switch unit of a type adapted to be assembled withcompanion units in an elecassembly, an open-end housing constituting aframe forthe switch, and including a back, an insulating base removablysecured tothe back, and contacts mounted on said base; a door forthehousing, a flanged plate slidably carried by the door, an insulatingbase on said plate between the flanges thereof, complementary contactscarried by the base on the flanged plate, said plate having acam-receiving slot formed therein, an eccentric cam within said slot, acam actuating element extending through, and operable exteriorly of saiddoor, and means associated with the frame and door for preventingclosure of the door except when the last named contacts are in apredetermined position on the door.

5. An electric switch including an enclosure, a hinged cover therefor,stationary contacts within the enclosure, a member carried in slidablerelation by said cover, contacts carried by and movable with theslidable member, and rotatable means adapted for slidably actuating saidmember only when said cover is in open position, said rotatable meansincluding an eccentric cam, and a cam operating element disposed foraccess exteriorly of the cover. v

6. A. switch assembly including a housing, a door hingedly attached tothe housing, paired switch terminals within the housing,paired blade'members slidably carried by the door, and arsaid door is in openposition, whereby to predetermine switching condition, upon movement ofthe door toward the housing.

1 Mid w u j adapn ;in'accordance' with in adouble-throw switchin anumber of differ-5" ent ways which, from the foregoing description;-will at once be apparentto those skilled in switch art; In Figs. 5 and 6I show, Qassemblyincludingaflhousing with the housing, movable contactscarried by between mamas trolling a plurality oi supply circuits, saidmeans including stationary switch contacts, carried bythehousingandapairotseparatelyoperablegroupsoi'movablecontactscarriedhytheclosure, manual control means formoving each of said closure-carried contact groups relative to theclosure. the contact groups being arranged for preventing energizationoi the supply circuits controlled by one of the contact groups, whilethe supply circuits controlled by the other of said contact groups areenergised.

FLOYD S. GREEN.

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